Soil nitrous oxide emissions in irrigated cotton are reduced by nitrification inhibitors applied with pre-plant anhydrous ammonia

Abstract

Key findings •• N2O emissions at the Gunnedah site were approximately 10 times higher than at the Emerald site, due to the wet soil conditions and high pre-season rainfall at Gunnedah which led to denitrification of N from pre-season anhydrous ammonia application. •• Two nitrification inhibitors, DMPS (“Big N-sure®”, Incitec Pivot Fertilisers) and nitrapyrin (“N-serve®”, Dow AgroSciences) directly injected into anhydrous ammonia during pre-plant N application delayed the conversion of applied ammonium in the soil to nitrate for a period of 2–3 months. •• At the Gunnedah site, cumulative N2O emitted was reduced by 86% (DMPS) and 65% (nitrapyrin), compared to untreated ammonia.